Electrical blanket and the like



w. F. CRADDICK ET AL ELECTRICAL BLANKET AND THE LIKE May 22,1923,

Filed April '7, 1922 17/522 m addr'ck F Patented May 22, 1923.

UNITED STATES PATENT OFFICE;

WILLIAM F. CRADDICK AND CHARLES M. UHLIG, OF CHICAGO, ILLINOIS, ASSIGNORS TO VIT-O-NE'I MFG. CO., OF CHICAGO, ILLINOIS, A CORPORATION OF WASHINGTON.

ELECTRICAL BLANKET AND THE LIKE.

Application filed April 7,

To all whom it may concern:

Be it known that we, \VILLIAM l CRAD- "DICK, a citizen of the United States, and CHARLES M. UHLIG, a citizen of Austria,

having declared my intention of becoming a citizen of the United States,both residing at Chicago, Cook County, Illinois, have invented certain new' and useful Improvements in Electrical Blankets and the like, of which the following is a specification.

This invention has to do with certain improvements in electrical blankets and the like, that is, blankets or like articles which are heated electrically by an electric current passed through them. We will state in the first place that the features of the inyentionherein disclosed may be used either in connection with articles of relatively large size-such as blankets, or articles of relatively small size such as pads, or may be used to advantage in connection with electrically warmed robes, dressing gowns, etc. For purposes of convenience in description and explanation, however, and also in order to simplify the specification, drawings and claims, we have-herein illustrated and'will describe the features of our invention as being incorporated within a blanket but in so doing we wish it clearly understood that we do not intend to limit the application or usefulness of the features of our invention to blankets or any other particular article of manufacture except as we may do so in the claims.

Bearing the foregoing in mind, we will first state than one of the main objects of the invention is to provide a blanket or the 7) like in which the electric conductors are woven into the body of the fabric, so that 40 they become and constitute an integral portion' of the weave of the fabric. By so doing an unusually satisfactory electrically conducting fabric is produced through which may be flowed the electric current to supply its heat. By so doing also the smoothness and uniformity and regularity of the completed fabric is greatly improved, since the creation of double thickness and other.objectionable elements is practically eliminated, i

.In connection with the foregoing, it is to be observed that in order to be able to Weave 'the' blankets in the most satisfactory and economical manner, it should be possible to *Weave them by a continuous weaving process 1922'. Serial No. 550,449.

that during the weaving operation the wire Wlll be properly woven into the fabricalong with the regular weft threads, the use of the wire in this process being so conducted that after a proper amount of material has been woven to constitute one blanket there will be a pause in the weaving of the wire so as to weave a certain section Without wire, after which the inweaving of the wire may be resumed and carried forward during the weaving of the next blanket section. In this way the weaving operation, may proceed practically continuously, and when a long section has been fabricated it may be cut up into the proper lengths for the individual blankets. One of the objects of the present invention is to provide a weaving process in which the foregoing operation and desirable results may be conducted and secured.

Another feature of the invention relates to the manner inwhich the weaving of the wire is conducted for each of the individual blanket sections. In this connection, it is to be remarked that the presence of sharp bends of wire at the very edges of the blanket is objectionable, since these edges are naturally subjected to more or less wear and hard service and therefore the insulation on the wire would rapidly become worn and possibly broken through, thus subjecting the user of the blanket to danger and also so increasing the fire hazards. Furthermore, the presence of the sharp bends of wire at the very edge of the blanket is also objectionable since the tendency for the wire conductor to become broken is thus enhanced, with corresponding danger of opening the circuit and thus not only making the blanket useless but also sometimes bringing about sparks or short circuits with the attendant dangers and fire hazards.

One of the objects of the invention is to provide a weave for the wire and other ele ments of fabric such that the cross weaving of the wire itself stops short of the edge of the fabric, the weaving of the weft and warp threads themselves continuing to the edges of the blanket, so that in. the comused in the foregoin 1. nary electric light on pleted work there will remain at each side a strip of fabric adjacentto the selvage within which however there is no wire but only threads or the like. Another object in this connection is to attain this result by the use of a more or less continuous weaving process. Still another feature of the invention relates to the provision of a weave in which there shall be provided all the way around the blanket a section of wireless fabric, the wires being confined to the space inside of said section, so that the completely woven article may be sewed or stitched clear around its edge without meeting or crossing any wires whatsoever. This will make it possible to apply to one or both faces of the blanket suitable facing of cloth or other material so aste give the blanket a completed and finished appearance and condition, such facing being sewed all the way around the edge of the blanket without any interference by constant rate, and the temperature which the blanket will ultimately attain will be that temperature at which the heat is being radiated or otherwise given off at the same rate as new heat is being generated. Naturally, for an article of this kind to be safe in use, it must be so arranged that it will never ordinarily exceed more than a cer tain desired temperature when used in the proper manner.

be thrown over the surface of the bed, so that they are more or less free to radiate heat from their top surfaces, and unless they are covered with a heavy covering of bedding or the like they will then radiate heat upwardly as well as downwardly onto the-bed and tllepatient. "When so used, it

is desirable to attain a temperature of sub-.

sta-ntially 100 F..

One of the objects of the present invention is to provide a blanket weave of such arrangement and proportions that when ner on an ordiof normal voltage the temperature of the blanket will 'never'exceed substantially 100 F. or'a. safe temperature;

Still another object of the invention is to provide a weave of such character that the maximum strength of the weave will be produced in those portions thereof which are normally subjected to the most severe usage and the greatest strains.

Other objects and uses of the invention will appear from a detailed description of the same, which consists in the features of construction and combinations of parts hereinafter described and claimed.

In the drawing:

Fig. 1 shows a fragmentary face view of a portion of a blanket weave embodying certain of the features of the present invention, the section of weave illustrated in this figure containing portions of two consecutive blankets at the line ofjunction between them, and the central portion of the weave being cut away so as to make the figure narrower:

Fig. 2 shows a face view of a section of completed weave as the samecomes off of the loom, illustrating the section of weave containing three complete blankets joined to ether; A Fig. 3 shows a face view of a completed blanket on enlarged scale as compared to Fig. 2, the blanket of Fig. 3 being provided with a sheet of facing material; and

Fig. shows a section taken on the line 4-i of Fig. 3, looking in the direction of the arrows.

Referring first to Fig. 2, we will state that the strip of blanket material in its entirety is designated by the numeral 5. It may be woven as a continuous strip .so as to provide a series of consecutive blankets 6, 7 and 8 betweenwhich there, are the spaces 9 and 10. Each of the blankets has woven into it a conductor wire 11 through which the electric current may be passed. It will be understood that the warp threads extend'lengthwise of Fig. 2. and the weft threads extend across the same, the material traveling lengthwise of Fig. 2 as it comes off the loom. These blankets are ordinarily intended to Referring now to Fig. 1, we will explain more in detail the particular weave therein illustrated. The same includes three groups of warp threads designated respectively 12, 13 and 14. The warp threads 12 are for the body of. the blanket and the groups of warp threads 13 and 14 are for the two borders respectively.

The weft thread is designated by the numeral 15. It extends back and forth with respect to the warp threads, over and underpoint A weaves over and under the various warps until there is reached a point adjacent to the border warp 13 where a mistake is made so that the weaving is reversed. The weaving then continues to the edge, .and the weft thread is then carried back in a regular manner through the warp threads 13, but a mistake is made then so .as to again reverse the weave, the weave then continuing re ularly through the body of the fabric back to the right hand side at the point B.

The wire 16 was previousl woven into the fabric by a regular weave through the warothreads from the pointC to the ooint D, where the wire was held ,at the right hand side of the weave while the Weft thrgad was woven from A across and back to The weft thread is now held at the point B while the wire is carried by a regular weave over and under the warp threads to the point E where the weave of the wire is temporarily discontinued, since the first blanket has been finished.

Thereafter the weft thread, commencing at the point B is woven through the border warps 14 in a regular weave but at the edge thereof a mistake is made so as to reverse the weave, and then the weave is continued in regular manner through the I body warps 12 and through the border warps'13 to the extreme left side of the weave The weft thread is then carried back the entire width of the blanket including the border to the right hand side by a regular weave, a mistake being made at'thepoint where the weft enters the right hand border warps so as to reverse the weave, and is then carried back again to the left hand side by a regular weave up to the point F just before entering the border warps 13 where a mistake is made so as to again reverse the weave. The reverse weave then continues through the border warps I 13 to'the left hand margin where the weft turns and runs back. through the borderwarps 13, the weave "being reversed by a mistake at a point between the border warps 13-and the body warps 12, the Weave then continuing in the regular manner to the extreme right hand side of the weave where the weft again turns and extends through 4 the border warps 14 by a regular weave to the point G where a mistake is made so as to reverse the weave, which then continues in regular fashion through the body warps 12 and border warps 13 to the extreme left hand side of the weave. The weft then turns and runs through the border warps 13 and through the body warps 12 in regular fashion until theborder warp 14 is reachedv where a mistake is made where thefw'eave reversed through the border warps 14 to the right hand side of the weave.

The section of weave just. described may be continued back and forth as many times as desired without carrying the wire into the weave, so as to establish one of the spaces 9 and 10 between consecutive 7 through said warps in regular fashion to the left hand side of the central warps to the 'point H. The weft thread has been held stationary at the right hand side at the point A during this operation. Itfis now picked up and carried to the. left hand edge of the central warps Eat the point J where a mistake is made and it passes through the border warps 13 with a reversed weave. It is then carried to the right through the border war s 13 a mistake being made at 9 the point as it enters the central warps 12 after which the weft thread is carried on through to the right hand edge of the border warps 14 witha regular weave. While the weft thread A is then held at the right hand sideof the Weave, the wire is again picked up and carried over to the right hand edge of the central warps-12with a. regular weave to the point L; Itis then held at the right hand side while the weft threadA is picked up and carried back through the border warps 14 to the point M where a mistake. is made,as it enters thecentral warps 12 through which it then passes in regular fashion to the left hand edge of the border 5 warps 13. It then comes back through the border warps 13 and center warps 12 to the pointN where a mistake is made and it then passes through the border warps 14 with a reversed weave. The weft thread A is then held at the right hand side while the wire is picked up and carried back through the central warps '12 with a regular weave to the edge of the border portion13. In this manner the weave is carried back and forth throughout the desired distance to provide a blanket of whatever size may be selected.-

Referring again to the diagrammatic view of Fig, 2, it will be observed that the blanket sections 6, 7 and 8 are illustrated as having the wire terminals 17 and 18 at the. right hand side. Ordinarily one of. these terminals is made longer than the other in a suflicient amount to allow it to be carried along the edge of the completed blanket to the same corner as that from which the other terminal projects, so that the two terminals can be brought together at the same corner.

I After the strip. has been woven it is cut After the 7 up at the sections 9 and 10 to provide the individual blankets. Owing to the fact that the wire is not woven'through theborder sections, and owing to the provision of in termediate sections such as 9and 10, there is provided around each blanket a continuous border within which there is no wire. The terminal wire 18 may be laid down along its blanket border so as to bring it to the same corner as thatfrom which the terminal 17 projects. This fact is clearly illustrated in Fig. 2. The wire terminal 18 may be allowed to lie loose along its border or may be secured thereto in any desired fashion. For example, it may be stitched or otherwise attached to a strip of tape 19, which strip in turn may be sewed along the wireless border of the blanket.

After the blanket has been completed to this point it is in a usable condition but ordinarily it will be desirable to provide a facing for each side so as to give it a'more finished appearance and also to more effectively protect the wires and their insulations from damage. lVe have therefore illustrated the facings 20 and 21 on the two faces of the blanket as shown in Fig. 4. The edge of the facing 21 is carried over the edges of the weave and laid against the opposite face of the borders of the weave, and then the facing 20 is set into place, and both of the facings, together with the border of the weave are sewed around as shown at 22 in Fig. 3. An eyelet 23 may be provided in the corner of one of the facings to allow the wire terminals 17 and 18 to be brought out without having to pass through any of the stitching.

It was previously explained that one of the objects of the invention is to provide an electrical blanket of such characteristics that it will never become overheated when used in the regular and intended manner. To this end we have found that by weaving approximately 1,240 feet of conductor equiyalent to 300 circular mils in cross sectional area of copper into a blanket approx imately 56x74 inches in size, there is provided a ,suflicient amount of electrical resistance to allow only such a current to flow under a voltage of approximately 110 volts as will constantly generate the amount of heat to maintain the blahiket at a temperature of substantially 100 F. when used in an ordinary sick room of approximately F. by laying the blanketon the top of the bed. A cable comprising 12 strands of N o. 36 wire of standard A. I. E. E. specifications is of approximately 300 circular mils cross sectional area and has a resistance of approximately 25.9 feet per ohm at a temperature of 100 F. Twelve hundred forty feet of this cable therefore have a resistance of substantially 47 .8 ohms, and will allow a current of substantially'23' amperes toilow,

with the dissipation of approximately 258.0 watts of energy.

A blanket of the above size has approximately 28.7 square feet of surface on each side. lVhen the blanket is thrown over the top of a bed so that it is substantially free to dissipate its energy from one surface, and assuming that it has reached a substantially constanttemperature, it will be dissipating approximately 8.9 watts per square foot of exposed surface, this being sufficient to retain the temperature substantially constant at F. above the temperature of the room. It will thus be seen that we have provided a blanket capable of generating and radiating approximately 8.9 watts per square foot of exposed surface in a substantially uniform manner over practically its entire surface.

\Ve wish to point out the fact that inas much as the weave of the wire is not carried clear throughto the edges of the blanket, it becomes necessary to occasionally vary the weave, and this variation we have herein spoken of as consisting of mistakes These mistakes simply consist in the passage of two or more warps simultaneously without inter-weave, thus causing a reversal of weave. It will be observed that these mistakes had been concentrated in the border lines between the border warps 13 or 14 as the case may be, and the body warps 12. This being the caseithe weave throughout the body portion is regular both ,for the warp thread and for the wire, so that the strength of the body portion is made as large as possible and irregularities are avoided; In like manner the weaves within the border sections 13 and 14 are alsoregular, and consequently, these portions of the blanket are also of maximumstrength. It is thus evident that we have provided a blanket and weave having a maximum of regularity and strength in those portions where these qualities are most desirable.

It will also be observed that although we have herein shown and 'described only a single embodiment of weave in which the wire stops short of the edges so as to establish border portions without wire, nevertheless, many other embodiments of weave might be provided with this characteristic, and therefore as far as this feature of the inventionis concerned, we do not intend to limitourselves to the particular weave illustrated except as we may do so in the claims.

We claim:

1. As a new article of manufacture an electric blanket or the like comprising a fabric and facings therefor, saidfabric consisting of body warps, border warps ateach side, wefts, and an insulated wire, the wefts being woven throughout the entire Width of the fabric from one extreme end to the other, and from one extreme selvage to the other extreme selvage, and the wire being woven only within the body warps and terminating at points within both ends of the fabric, whereby there is produced a fabric consisting of a central portion containing insulated wire woven into the fabric together wlth an integral continuous border of wireless fabric completely surrounding the wire:

containing'body portion, the sheets of facing material lying against the faces of the fabric.

and reaching over' the border portion, and a line of stitching joining the sheets of facing material to the wireless border portion, substantially as described.

2. As a new article of manufacture an electric blanket or the like comprising a fabric and a facing therefor, sald fabric consisting of body warps, border warps, at each side, wefts, and an insulated wire, the wefts being Woven through the entirewidth of the fabric from one extreme end to the other and from one extreme selvage to the other extreme selvage, the wire being woven at points within both ends of the fabric, whereby there is provided a fabric consisting of a central portion containing insulated wlre woveninto the fabric together with an integral continuous border of wireless fabriccompletely surrounding the wire containing body portion, the sheet of facing material lying against one "side of the fabric and reaching over the border portion, and aline of stitching joining the sheet of facing material to the wireless body portion, substantially as described.

3. As a new article of manufacture an electric blanket or the like comprising a fabric, said fabric consisting of body warps, border warps at each side, wefts, and an insulated wire, the w'efts' being woven throughout the entire width of the fabric from one extreme end to the other and from one extreme selvage to the other extreme selvage, and the wire being woven only within the body warps and terminating at points within :both ends of the fabric,

whereby there is produced a fabric consist ing of a central portion containing insulated wire woven'into the fabric, together with an. integral continuous border of wlreless fabric completely surrounding the wire con wire, throughout .theentire width of the fabric ,der warps at each side, wefts, and an the wefts' being woven one extreme end to the other and from one extreme selvage to'the other ex-, treme selvage,"and the wire being woven in the body wraps, whereb anew article of manufacture an electric blanket or the like comprising a abric, said fabric consistingof body warps,

only within the body warps and terminating at points within both ends of the fabric, whereby there isproduced a fabric consisting of a central portion containing insulated wire woven into the fabric, together vxith an integral continuous border of wireless fabric completely surrounding the wire containing body portion, substantially as described. 5, As anew article of manufacture an electric blanket or the like, comprising a fabric, said fabric consisting of body warps, border warps at each side, Wefts, and an insulated wire, the wefts being woven throughout the entire width of the fabric from one extreme end to the other, and from one extreme selvage to the other extreme sel rage, and the wire beingswoven only with-,

there is produced a fabric consisting oa central portion containing insulated 'wire woven into the fabric together with a border of wireless fabrieat each side thereof, substantially is described. only within the body warps and terminating 6. As a new article of manufacture an electric blanket or the like comprising a fabric consisting of body warps, border warps at each side, wefts, and an insulated wire, the wefts being woven throughout the entire width of the blanket from one extreme end to the other and from one extreme selvage to the'other extreme selvage, and the wire being woven only within the body warps, the warps at one side occupying a greater width than at the other side, whereby there is produced a fabric consisting of a central portion containing insulated wire together withan integral border of wireless,

fabric at each side, one of said borders being wider than the other, substantially as described. I

7. As a new article of manufacture an electric blanket or the like consisting of a fabric comprising body warps, border warps at each side, wefts, and an insulated" wire, the wefts being woven throughout the entire width of the fabric from one extreme endv to the other and from one extreme selvage to the other extreme selvage, and the wire being interwoven with the wefts but only in the body portion and terminating at points within both ends of the fabric, the weave of the wire into the body wa regular, and the weave of the we with the body warps and with each set of border -Tarps being regular, and there being mistakes in the weave of the wefts at points on s being the margins between the body and border warps, whereby there is, produced a fabric 4 consisting of a central portion containing insulated wire woven into the fabric together with an integral continuous border of wireless fabric comdpletely surrounding the w wire containing bo portion,'and whereby the body and border portions are respectively made of a maximum strength and uniformity of weave, substantially as described.

8. As a new article of manufacture an electric blanket or the like consisting of a fabric comprising body warps, border warps, at each side, wefts, and an insulated wire, the wefts being woven throughout the entire width of the fabric from one extreme selvage to the other extreme selvage, and

p the wire being interwoven with the wefts but only in the body portion, the weave of the wire into the body warps being regular and the weave of the wefts into the body warps and with each set of border warps being regular, and there being mistakes in with an integral border of wireless fabric at each side of the body portion, and whereby the body and border portions are respectively made of maximum strength and uni forniity of weave, substantially as described.

7 9. The method of weaving electric blan= hate or the like which consists in using a set of body warps and a set of border warps at each side thereof, weaving a weft thread back and forth through the body warps and through both sets of border warps the desired number of times to establish a section of weave without wire, thereafter continuing the weave of the weft into the body and border warps from one extreme selvage to the other extreme selvage and interweaving an insulated wire therewith from the margin between the body warps and one set of border warps -to the margin between the body warps and the other set of border warps, continuing such interweaving a desired distance according to the length which it is desired to contain wire, thereafter discontinuing the weave of the wire and continuing the weave only with weft thread from one extreme selvage to the other extrenie selvage through both sets of border warps and the body warps, continuing such weave without wire for a sufficient distance to establish contiguous marginal portions for two contiguous blankets, thereafter recommencing the interweaving of the wire, etc, substantially as described.

\VILLIAM F. CRADDICK. CHARLES M. UHLIG. 

